The underground network continued to expand


More than 257 km of new lines were added to the public transmission network in 2019 (including overhead lines that were undergrounded).

RTE also replaced more than 376 km of overhead and underground lines on its network.

Closer look

Better understanding

Closer look

Overhead and underground lines: Complementary technologies

As part of its public service contract with the French state, signed in May 2017, RTE committed to not increase, and even to decrease, the total length of overhead lines on its network (see chart, total overhead lines).

Since 2017, 95.5% of the new 90 kV and 63 kV lines brought into service have been underground. RTE is also working to “take down” existing overhead lines. As technologies evolve, RTE is burying high-voltage lines more and more often.

Underground lines current represent:

  • 6% of all 63/90 kV lines;
  • 6% of all 225 kV lines;
  • a negligible share of 400 kV lines (0.03%).

Better understanding

400 kV and 225 kV Voltages


Underground

A total of 45 km of new 225 kV underground lines were brought into service in 2019. The main completions were:

  • The 225 kV Quatre Seigneurs–Saumade underground line in the Hérault, to enhance security of supply in the Montpellier metropolitan area;
  • The commissioning of the 225 kV Béziers-Est-St-Vincent double-circuit line in the Hérault, to increase security of supply in the Béziers metropolitan area;
  • The inauguration of the 225 kV Grimaud–Trans line in the Var, to enhance security of supply in that department;
  • The commissioning of the 225 kV Saclay–St-Aubinand Saclay–Villeras lines in the Essonne, to connect a substation.

 

Overhead

RTE replaced conductors on nearly 205 km of overhead lines operated at voltages of 400 kV and 225 kV in 2019, primarily as part of:

  • The replacement of the 225 kV Châtillon-sur-Seine – Darcey – Rosièresline in Côte-d’Or;
  • The replacement of the 400 kV Chesnoy – Cirolliersline in Essonne and Seine-et-Marne;
  • The inauguration of the 225 kV Grimaud – Trans line in the Var, to enhance security of supply in that department;

The replacement of the 225 kV Carrières – Roye – Valescourt line in the Oise.

Closer look

Better understanding

63 kV and 90 kV Voltages


Underground

The length of underground lines operated at voltages of 63 kV and 90 kV increased in 2019, as 175 km of new lines were added. RTE notably brought into service:

  • The Gourdan – Lestelle63 kV line in the Haute-Garonne;
  • The l’Argentière – Serre-Barbin63 kV line in the Hautes-Alpes;
  • The Bains-les-Bains – Pouxeux63 kV line in the Vosges;
  • The Langogne – Montgros63 kV line in the Lozère.

 

Overhead

Conductors were replaced on certain 63 kV and 90 kV overhead lines representing 159 km in all. Examples included:

  • The Grisolles – Montdauphin63 kV line in the Hautes-Alpes;
  • The Baraqueville – Thuries – Pré-Grand63 kV line in the Tarn;
  • The Armonville – Thionville90 kV line in the Loiret;
  • The Changy – Riorges63 kV line in the Loire.

Closer look

Better understanding